plague

plague

plague, any contagious, malignant, epidemic disease, in particular the bubonic plague and the black plague (or Black Death), both forms of the same infection. These acute febrile diseases are caused by Yersinia pestis (Pasteurella pestis), discovered independently by Shibasaburo Kitasato and Alexandre Yersin in 1894, a bacterium that is transmitted to people by fleas from rats, in which epidemic waves of infection always precede great epidemics in human populations. Sylvatic plague, still another form, is carried by other rodents, e.g., squirrels, rabbits, chipmunks, in rural or wooded areas where they are prevalent.

Bubonic plague, the most common form, is characterized by very high fever, chills, prostration, delirium, hemorrhaging of the small capillaries under the skin, and enlarged, painful lymph nodes (buboes), which suppurate and may discharge. Invasion of the lungs by the organism (pneumonic plague) may occur as a complication of the bubonic form or as a primary infection. Pneumonic plague is rapidly fatal and is the only type that can be spread from person to person (by droplet spray) without intermediary transmission by flea. In the black form of plague, hemorrhages turn black, giving the term "Black Death" to the disease. An overwhelming infection of the blood may cause death in three or four days, even before other symptoms appear.

In untreated cases of bubonic plague the mortality rate is approximately 50%-60%; pneumonic plague is usually fatal if not treated within 24 hours. Such antibiotics as streptomycin and tetracycline greatly reduce the mortality rate. Vaccine is available for preventive purposes. Rodent control is important in areas of known infection.

History

The earliest known visitation of the plague to Europe may have occurred in Athens in 430 B.C., but it is unclear if the disease that afflicated Athens was caused by Yersina pestis. A disastrous epidemic occurred in the Mediterranean during the time of the Roman emperor Justinian; an estimated 25% to 50% of the population is reported to have succumbed. The most widespread epidemic began in Constantinople in 1334, spread throughout Europe (returning Crusaders were a factor), and in less than 20 years is estimated to have killed three quarters of the population of Europe and Asia. The great plague of London in 1665 is recorded in many works of literature. Quarantine measures helped contain the disease, but serious epidemics continued to occur even in the 19th cent. The disease is still prevalent in parts of Asia, and sporadically occurs elsewhere (approximately 2,500 cases worldwide annually). In Surat, India, in 1994, 5,000 cases of pneumonic plague were reported in an outbreak; an estimated 100 people died, and more than 400,000 people fled the city. Because the number of cases of plague has been increasing annually, it is categorized as a re-emerging infectious disease by the World Health Organization.

Bibliography

See P. Ziegler, The Black Death (1969); W. Whitman, Travel in Turkey, Asia Minor, Syria and Egypt (1971); R. S. Gottfried, The Black Death (1983); G. Twigg, The Black Death: A Biological Reappraisal (1985); R. Horrox, ed., The Black Death (1994); O. J. Benedictow, The Black Death 1346-1353: The Complete History (2004); W. Orent, Plague (2004); J. Aberth, The Black Death: The Great Mortality of 1348-1350 (2005); J. Kelly, The Great Mortality: An Intimate History of the Black Death (2005).

Infectious fever caused by the bacterium Yersinia pestis, carried by the rat flea. It usually spreads to humans only when the flea runs out of rodent hosts. It takes three forms. Bubonic, the mildest, has characteristic swollen lymph nodes (buboes) and is spread only by the flea. It accounts for three-fourths of plague cases. Pneumonic plague has extensive lung involvement and is spread in droplets from the lungs; it is often fatal in three or four days without treatment. In septicemic plague, bacteria overwhelm the bloodstream and often cause death within 24 hours, before other symptoms have a chance to develop. In the 14th century, plague ravaged Europe and Asia and was called the Black Death. Plague does not respond to penicillin, but other antibiotics are effective. Sanitary measures against fleas and rodents, quarantine, and extreme caution in handling infectious materials help to suppress epidemics. A vaccine can prevent plague.

Acute, highly contagious viral disease of ruminants (including wild cloven-hoofed ones), common in Africa, the Indian subcontinent, and the Middle East. The virus spreads by close direct or indirect contact. It is the most severe infectious disease of cattle, with sudden onset and high mortality; fever and loss of appetite are followed by symptoms including eye and nasal discharge, laboured breathing, and diarrhea; prostration, coma, and death follow within 6–12 days. Local eradication depends on controlling it in wild animals and eliminating infected domestic animals; vaccination combined with quarantine is effective.

Antonine Plague, an ancient pandemic in 165–189 AD brought back to the Roman Empire by troops returning from campaigns in the Near East

Third Pandemic, a major plague pandemic that began in China in 1855, spread via trade routes around the world. This episode was considered active until 1959, when worldwide casualties dropped to 200 per year.